Camshaft: Belt or Chain Drive?

just buy a 2 stroke if you are worried, problem solved

Unless you have a 186 with fibre gearing!

Wow. Looking at the lower photo. It's like it's just a piece of plastic holding the chain. Surely this isn't how all engines are designed. I'd like a metal tensioner/idler please.

Nothing wrong with them. They knocked that bloody loud before they let go. So if you were dumb enough to keep driving, then you were the dumb-arse, not the engine.
And Holden engines did do it too.
Still rather have a chain myself.

Some numbers for you. Timing belt replacements are generally in the $300-1200 range depending on the model and what should be replaced. Replacement intervals on what modernish engines that still have them are 100-150k km's (there are some exceptions that need doing at lower kms but not many now, mainly a few poorly engineered Euro dungheaps that are foolish for the average garage paying motorist to own in NZ anyway). Chain replacements are in the $800-2500 range depending on the model and what needs to be replaced, if by chance your particular engine doesn't have a repair kit available, either genuine or aftermarket, and all of the components involved need replacing and must be bought as individual parts, trust me the cost of the job can approach the top figure very quickly. If you had to undertake a chain replacement at 90-200k kms as many have had to due to stretch and resulting engine management issues, what is offering you the better value for money over the life of that car? The reality is that chains are only an advantage if the system is engineered right and it is supplied with clean good quality oil over its ENTIRE life. Not just when it was new and under warranty and was (hopefully) dealer serviced as it should have been with the right oil, but its entire life.

"funny" isn't it. Yamaha and Kawasaki bikes had the same sort of issues in the 1980's with the GPZ/GPX XJ and FJ range of bikes.
The "fix back then was to drill and tap the tensioner and fit a locking bolt so the tensioner couldn't back off.

Franc-What you say makes sense and lines up with my experience --BUT
On the whole would it be fair to say that MOST jap cars with this current camchain tech are not failing in that 100-200k range --and those that do have a readily available kit for about $1000 incl labour.
it seems to me that Its the euro's that have dropped the ball on this front--particularly VAG group and BMW

I change my cars regularly. It's a bit of weird thing for me. I get bored with cars and sell and by something different constantly. Usually go through 3 / to 6 cars a year. Have done that most my life. Now and again I find one I'll keep for a couple of years, but not often. I only buy older vehicles. Nothing over 6k in general. I can only go by experience. And I cant remember over my life time having to ever spend money on a timing chain. That's zero $ spent ever. How many times have i had to do a cambelt? Way too many for my liking with thousands spent over the years. My last cambelt a couple of years ago cost me $980. From experience they dont come a lot cheaper to do it properly, and Im talking chain, tensioner, idler and water pump. Perhaps I have just struck the more costly ones.

My last two purchases were cam chain engines and that was a main factor in my buying them. Not knocking your advice, I know you are pretty on to it. But I think I'll stick with my preference for cam chain engines. There isn't much you can say that will change that. Have had way too much luck with them over the years. Zero $ spent on camchain vs thousands spent on cam belts. Yeah, I'll stick to my chain driven engines if given a choice.

Well, I certainly started off a whole CHAIN of comments (pun definitely intended!) - great to read all of your thoughts.
One correspondent wrote about BMC A engines: easy to fit a new chain on a Morris Minor engine, not so easy on a transverse 1100's engine. I removed the radiator, that was the easy part. More difficult was getting at the tab washer on the end of the crankshaft. I used a hammer and punch - and a mirror to try to see what I was doing. (I guess a dentist would have no trouble!)

Read somewhere the Honda chains are recommended changed at 300000kms.

If you talking 186 holden, only ever heard folk
rave how good they are. Old man had great
run out of his.